This invention relates to a vacuum insulating glass (IG) unit. More particularly, this invention relates to a vacuum IG unit having a seal for sealing an area proximate an aperture used during pump-out operations.
Vacuum IG units are known in the art. For example, see U.S. Pat. Nos. 5,664,395, 5,657,607, 5,891,536 and 5,902,652, the disclosures of which are all hereby incorporated herein by reference.
Prior art FIGS. 1-2 illustrate a conventional vacuum IG unit. IG unit 1 includes two spaced apart sheets of glass 2 and 3 which enclose an evacuated or low pressure space 16 therebetween. Glass sheets 2 and 3 are interconnected by peripheral or edge seal of fused solder glass 4 and have an array of support spacers/pillars 5 therebetween.
Pump out tube 8 is sealed by solder glass 9 to a double drilled aperture or hole which passes from an interior surface of glass sheet 2 to the bottom of recess 11. Double drilling typically means that two separate drilling diameters are used during formation of the hole so that its diameter is different at one surface of the substrate than at the other surface of the substrate. Two separate drilling steps may be required. A vacuum is attached to tube 8 (prior to the tube being sealed) so that the interior space 16 between sheets 2 and 3 can be evacuated to create a low pressure area. After evacuation, an end of tube 8 is melted to seal the vacuum in space 16. Optionally, getter 12 may be provided within recess 13 to counteract any rise in pressure due to any out-gassing from the glass.
FIG. 3 is a side cross sectional view of another conventional vacuum IG window unit. This unit differs from the FIG. 1-2 unit, in that its glass sheets are of different sizes so as to provide an L-shaped step around the unit""s periphery, on which edge seal 4 is to be at least partially located. Pump-out tube 8 in FIG. 3 projects outwardly above a surface of substrate 3, even after evacuation of space 16 and sealing of the tube. Moreover, the FIG. 3 unit includes low-E coating 6 on the interior major surface of glass sheet 3.
Different techniques have been utilized in evacuating vacuum IG units, and different types of pump-out structures have been discussed.
U.S. Pat. No. 5,902,652 to Collins is incorporated herein by reference and discloses, for example, a double drilled pump-out hole or aperture in its FIGS. 4a and 4b. A pump-out tube extends through the hole and is used in evacuating the internal space. The tube is sealed to the interior surface of the substrate with solder glass cement.
U.S. Pat. No. 5,897,927 discloses the use of a pump-out tube to evacuate an internal space within a glass enclosure. The pump out tube is sealed to the unit using glass frit paste.
Unfortunately, the pump-out techniques and procedures disclosed in the aforesaid ""652 and ""927 patents are less than desirable for at least the following reasons. The use of pump-out tubes that must be permanently sealed to glass substrate(s) is not always desirable. Nor is the need for double drilling holes. These are burdensome and/or expensive.
It is apparent from the above that there exists a need in the art for a vacuum IG unit, and corresponding method of making the same, in which the pump-out structure and techniques for evacuating the interior are simplified and less burdensome and/or costly.
This invention will now be described with respect to certain embodiments thereof, accompanied by certain illustrations.
An object of this invention is to provide a vacuum IG window unit including a wafer or plate type sealing member used in sealing off an area proximate a pump-out aperture.
Another object of this invention is to eliminate the need for double-drilling of pump-out holes.
Another object of this invention is to provide a simplified technique for evacuating an internal area of a vacuum IG unit and subsequently sealing the same.
Another object of this invention is to fulfill any and/or all of the above-listed objects and/or needs.
Generally speaking, this invention fulfills any or all of the above described objects or needs by providing a method of evacuating an internal cavity of a vacuum insulating glass (IG) window unit, the method comprising the steps of:
providing first and second spaced apart glass substrates defining a space therebetween;
providing an aperture or passage, at least one end of which accesses the space between the substrate;
providing a plurality of spacers disposed between the first and second glass substrates for spacing the substrates from one another in order to maintain the space therebetween;
positioning a sealing member over at least an end of the passage or aperture;
evacuating the space by causing gas or air to flow therefrom through the passage or aperture and thereafter through spaces defined between sealing elements located between the sealing member and either the aperture or the first substrate.
This invention further fulfills any or all of the above described needs and/or objects by providing a method of evacuating an internal cavity of an insulating panel, the method comprising the steps of:
providing first and second spaced apart substrates defining a space therebetween;
providing an aperture in the first substrate;
providing a plurality of spacers disposed between the first and second substrates;
providing an edge seal around an edge portion of at least one of the substrates, the edge seal being provided at least partially between the first and second substrates;
positioning a sealing member over the aperture in a manner such that the sealing member is spaced from the first substrate; and
evacuating the space between the substrates by causing gas or air from the space to flow therefrom through the aperture in the first substrate and thereafter through at least one space defined between portions of at least one sealing element attached to a surface of the sealing member.
This invention further fulfills any or all of the above-described needs and/or objects by providing a thermally insulating glass panel comprising:
first and second spaced apart glass substrates defining a space therebetween having a pressure less than atmospheric;
a pump-out aperture defined in the first substrate;
a plurality of spacers disposed between said first and second glass substrates for spacing said substrates from one another in order to maintain the space therebetween;
a sealing member over the aperture; and
at least one sealing element disposed between said sealing member and a major surface of said first substrate in order to seal off an area proximate said pump-out aperture, said at least one sealing element being deformable when subjected to heat so that a pump-out opening therein can be closed after a pumping-out procedure has been performed.